Terminal Voltage: Solving for 12V Motorcycle Battery Charger

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In summary, the problem involves finding the terminal voltage of a motorcycle battery being charged by a current of 11.7 A, with an internal resistance of 0.520 Ω. The equation used is Vterminal = ε - IR, and the solution is determined to be -5.916 V. However, further clarification is needed on the sign of the current and its relation to the internal resistance and battery emf.
  • #1
burnst14
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2

Homework Statement



(a) Find the terminal voltage of a 12.0-V motorcycle battery having a 0.520 Ω internal resistance, if it is being charged by a current of 11.7 A.

(b) What is the output voltage of the battery charger?


Homework Equations



ΔV = ε - IR
or
Vterminal = ε - IR

The Attempt at a Solution



ΔV = 12 - (11.7*0.52) = 5.916 = Vterminal

This is incorrect. WebAssign also returned this information:

"What is the sign of the current if it is flowing into the positive terminal of the battery? How is terminal voltage related to the internal resistance and battery emf?"

So I made it negative and submitted the response: -5.916

Still wrong. What am I missing?
 
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  • #2
You have an external voltage (the "charger") supplying a given current into the battery (which includes an internal resistance). Draw the circuit and pencil in the current and potential drops for the given current.
 
  • #3
My physics teacher was able to help me. I was missing the fact that the current would have to be made negative since the charger was inputting a current. Thanks though!
 

FAQ: Terminal Voltage: Solving for 12V Motorcycle Battery Charger

1. What is terminal voltage?

Terminal voltage is the potential difference between the positive and negative terminals of a battery. It is measured in volts and represents the amount of electrical energy available to power a device or system.

2. How do I measure the terminal voltage of a 12V motorcycle battery?

To measure the terminal voltage of a 12V motorcycle battery, you will need a voltmeter. Set the voltmeter to the DC voltage setting and connect the positive lead to the positive terminal of the battery and the negative lead to the negative terminal. The voltmeter will display the terminal voltage in volts.

3. Why is it important to solve for terminal voltage in a 12V motorcycle battery charger?

It is important to solve for terminal voltage in a 12V motorcycle battery charger because it ensures that the battery is receiving the correct voltage for charging. If the terminal voltage is too low, the battery may not charge properly and if it is too high, it can damage the battery.

4. How can I calculate the terminal voltage for a 12V motorcycle battery charger?

The terminal voltage for a 12V motorcycle battery charger can be calculated using Ohm's Law, which states that voltage (V) equals current (I) multiplied by resistance (R). In this case, the resistance would be the internal resistance of the battery. So, the formula would be V = IR. Alternatively, you can use a circuit simulator or consult the charger's manual for the terminal voltage.

5. What should the terminal voltage be for a fully charged 12V motorcycle battery?

The terminal voltage for a fully charged 12V motorcycle battery should be around 12.6 volts. However, this can vary slightly depending on the temperature and age of the battery. It is important to consult the manufacturer's specifications for the specific terminal voltage range for your battery.

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